Interlocking system for railroads



Sept. 22, 1931. F. DODGSON INTERLOCKING SYSTEM FOR RAILROADS Filed March20, 1930 ATTORNEY Patented Sept. 22, 1931 UNITED STATES rmx L.DODGSON,,OF ROCHESTER, NEW YORK, ASSIGNOB 1'0 GENERAL RAILWAY SIGNALCOMPANY, OF ROCHESTER, NEW YORK INTEBLOGKIHG SYSTEM FOR RAILS/DADSApplication filed March 20, 1980. Serial No. 487,472.

This invention relates to power interlocking systems, and moreparticularly pertains to the remote control of switch machines andsignals used in such systems, and to the elec- 5 tric interlockingbetween such remotely controlled functions.

In interlocking plants, where a large number of switch machines andsignals are governed from a central tower, it is desirable for m reasonsfamiliar to those skilled in the art, to have those signals governingtrafiic over a particular track switch dependent upon the position andlocked condition of that switch. It is further desirable that all suchgoverning signals shall give their most restrictive indications beforethe associated track switch is allowed to be operated to a new position.

Also, in interlocking plants, any one articular track section may beincluded in a go large number of the possible route combinations, whichmakes it desirable to provide each of the signals, controllin trafiicover a given section, with individua control. In other words, theclearing of the signals governing a certain route may be dependent andinterlocked with the associated switch machines and still be dependentupon individual control to establish the final clearin and the directionof traflic to be set up over t at route,

as distinctive from that type of remote control in which the se uence ofoperation and the presence of a train establishes the direction oftraflic over a van route.

With the above an other considerations in mind, it is proposed toprovide in accordance with the present invention an interlocking systemof the remote control ty e having the switch machine and si al circuitsinterlocked to revent contro of the switch machine unt the associatedsignals give most restrictive indications. The interlockin system is tobe further provided with indivi ual control of the signals, whichcontrol is also interlocked with the associated switch machine. Also,the switch machine remote control circuit is to be organized to preventthe control lever in the tower from be 0 erated out ofcorrespondence'with the circuit controlling relay associated therewith.V

5 Another object of the invention, is to provide that the relayindicating the position and locked condition of a particular trackswitch, shall also indicate the correspondence of the remote controlrelay, the remote controller and the signals with the position andlocked condition of that particular track switch.

Various other objects, purposes and characteristic features of thepresent invention will be in part obvious from the accompan ing drawing,and in part pointed out as t e description of the invention progresses.

The single figure of the accompanying drawing represents in adiagrammatic manner one specific interlockin system with its circuitsand devices arrange and constructed to embody the present invention.

With reference to the single figure of the drawing, a track switch TS isconventionally shown as operated b a suitable switch machine includedwithin the dotted rectangle SM. This switch machine SM is preferabl ofthe type described in the patent to W. Howe Patent N 0. 1,466,903, datedSeptember 4, 1923, but may be any other suitable switch machine havingthe usual armature A and field windin F and being capable of operatingsaid trac switch TS to either of two extreme locked positions. Also,included within the switch machine SM is a brake BR normally biased to abraking position and included within the operating circuit of the switchmachine SM, so that it will be actuated to a released condition upon theapplication of wer to said switch.

movable contact 5, which makes contact between a pair of fixed contactswhen in a normal position and a certain other pair of fixed contactswhen in the reverse position, is caused to assume these positions incorrespondence with the switch machine SM at the end of each of its 0tiona.

The contacts, shown wnhin a dotted rectangle designated PD, are known aspoint detector contacts, and include a movable contact block 6 ofinsulating material which is caused to assume extreme normal or reversepositions when the track switch T8 is in corresponding positions andlocked; and which is caused to assume an poli- Ill tion when the trackswitch TS is being 0 rated from one extreme position to anot er, or anyother such time that said track switch is unlocked. Contacts 7 and 8 aremounted on this movable contact block (5, which make contact betweentheir respective pairs of fixed contacts when in the normal or reverseextreme positions only.

The point detector contacts PD include, a shunt contact 9 which isactuated to a noncontacting position when the contact block 6 is in anormal extreme position and assumes a biased contacting position at anysuch time that said movable contact block 6 is not in an extreme normalposition; and also, a shunt contact 10 which is actuated to anoncontacting position when the movable contact block 6 is in a reverseextreme position and assumes a biased contacting iosition at any suchtime that said movab e contact block 6 is not in an extreme reverseposition.

Associated with the switch machine SM is a circuit controller OR of. themechanical stick or toggle type circuit controller which is operated bya control relay Z which in turn is controlled from the interlockingtower TR. The conditions, under which the remote controller CR may beoperated, are determined by the positions assumed by a switch repeaterrelay SR and normal and reverse indication repeating relays N1 and RIrespectively associated with t ie contacts PD.

A normal operating coil NC and a reverse operating coil RC serve tooperate a plurality of contacts of the controller OR to correspondingnormal or reverse positions respectively, in which positions saidcontacts are both electrically and mechanically held until the nextsucceeding operation.

The track switch TS allows trafiic to be routed over the main trackrepresented by rails 1, or allows traffic to be routed onto a passinsiding PS represented by rails 2. A detector track section TE isassociated with the main track and the fouling portion of the passingsiding and has the usual track batter 13 and track relay T. At the westend 0 the detector track section TE, signals and 8*, each being capableof giving two or more indications, govern the trafiic passing in an eastbound direction over the main track or the passing siding respectively,in accordance with the position of the track switch TS as indicated bythe indication relays N1 and RI, and also in accordance with theposition of a remotely controlled relay Z which is controlled from thetower TR.

Associated with the track relay T and the remotely controlled relays Zis a section locking relay SLR which is energized through a circuitincluding the front contact of the track relay T and such other relays,for example, as approach locking relays, route locking relays, and thelike, (not shown) commonl used in interlocking circuits. he relay 1 isof the polar magnetic stick type, that is, when its contacts areoperated to an extreme position, they are held in that position by aermanent magnet. Similarly, the relay Z is of the polar-neutral type inwhich the polar contacts operate the same as the polar contacts of relayZ, and in which a neutral contact assumes the same actuated positioneach time that the relay Z is energized.

In the interlocking tower represented by the dotted rectangle TR, aminiature track diagram corresponding in every particular to the actualtrack layout of the interlocking plant includes a miniature passingsiding ps and detector track section te. An indicator light I, locatedabove the track section te, indicates the occupancy of the detectortrack section TE associated therewith.

A switch machine lever SML is provided for controlling the track switchTS from the tower. This lever SML operates a switch of the two-positionquick acting tumbler type having a lock L which, when deenergizcd,prevents movement of the switch contacts to a new position. The )ositionof the lever SML determines the application of positive or negativepotential upon a control circuit including an indication relay IR fromany suitable source such as battery BT haviug its midpoint connected toa common wire C. A signal lever SL operates a switch of thethree-position type for placing positive or negative potential from anysuitable source such as battery BT upon the control circuit of relay Zlocated at the switch machine for governing the signals S and S It willbe noted, that throughout the description of this embodiment of thepresent invention. that the opposite terminals of all sources ofelectrical potential will be designated as 13+ and B-, which sources maybe the same sources of supply or other suitable sources all inaccordance with the practical application of the invention. It is to beunderstood that these sources of electrical potential are preferablylocal to the points indicated, also that they may be either directcurrent or alternating current according to the circumstances to be metin practice.

It is believed that the usefulness of the system and the interrelatedfunctions of the various circuits and devices will be more readilyunderstood by further description being given from the standpoint of theoperation of the interlocking system taken as a whole.

Operation of the system train to proceed in an east bound direction Innover the track section TE, when the signal lever SL is in a right-handextreme position.

With the track section TE unoccupied, the track relay T is energized bythe battery 13 in the usual well known manner, w ich causes the frontcontact 15 of said track relay T to complete the circuit for the sectionlocking relay SLR. This energizing circuit is traced as follows :fromthe positive terminal of a suitable source of electrical potentialindicated as B+, through front contact 15 of track relay T, wire 16,winding of relay SLR, to the negative terminal of the suitable sourceindicated as B- The section locking relay SLR governs the normal andreverse energizing circuits of the remote controlled relay Z. The normalenergizing circuit of this relay Z is traced as follows :from thepositive terminal of battery BT, through wire 18, lever SML in aright-hand extreme position, wire 19, winding of the indicating relayIR, wire 20, front contact 21 of relay SLR, wire 22, winding of rela Zwire 23, front contact 24 of relay SL through the common wire C to themidpoint of the battery ET. The control relay Z has its polar contactsthus energized to right-hand extreme positions.

With the polar contact 25 of relay Z in a right-hand extreme position,the ener izing circuit of the switch repeating relayl R is completedwhich also includes the olding circuit of the circuit controller CR.This normal energizing circuit for relay SR is traced as follows :fromthe positive terminal of a suitable source of electrical potentialindicated as B+, through back contact 26 of indicating relay RI, wire27, polar contact 25 of rela Z in a normal position, wire 28, winding Cof circuit controller CR, wire 29, contact 30 in a left-hand normalposition, wire 31, contacts 7-32, wire 33, shunt contact 10, wire 34,winding of relay SR wires and 36, contacts 8-37, wires 38 an 39, to thenegative terminal of the suitable source indicated as B- The energizingcircuit for the relay N1 is completed, as the neutral front contact 40of relay SR is in an energiz 'tion and the polar contact 41 of relay SRis in a left-hand normal extreme position, which ener circuit is tracedas follows :-from the positive terminal of a suitable source ofelectrical potential indicated as B through front contact 40 of relaySR, wire 45, polar contact 41 of relay SR in a left-hand position, wire46, winding of relay NI, wire 4 back contact 48 of relay III, to thenegative terminal of the suitable source indicated as B.

The signals 8 and S are interlocked through contacts on the relays NIand R1 in a manner that the signal S me be cleared when the track switchTS isin a. normal lockedpoeition,mdtheeignsls'meybe cator lamp I. Thisis accom cleared when the track switch TS is in a reverse lockedposition. Thus, should the o erator at this time move the control leverto a ri ht hand position, the remote control relay would be energizedand complete the energizing circuit for clearing the signal S.

Let us assume that the operator moves the signal lever SL to aright-hand extreme position, which ener 'zes the relagaz' from thepositive termina of battery T, through 49, lever SL in a right-handextreme position, wire 50, winding of relay Z, common wire C to themidpoint of battery ET. The circuit for clearing signal S is nowcompleted with the front contact 51 of relay Z in an energized osition.This circuit is traced as follows rom the positive terminal of asuitable source of electrical potential indicated as 3+, through frontcontact 51 of re lay Z, wire 52, polar contact 53 of relay Z in aright-hand position, wire 54, back contact 55 of relay RI, wire 56, fromcontact 57 of relay NI, wire 58, through the control devices of ex nalS, to the negative terminal of the suitab e source indicated as B-.

If a train accepts signal S and passes onto the track section TE, thefact is indicated in the tower TR by the illumination of the indilishedby the deenergization of the track re ay T which in turn 0 ns thecircuit of the section locking rela LR. The dropping ,of the frontcontacts 21 and 24 of the rela SLR opens the normal energizing circuit o;the relay Z and shunts the winding of this relay through wire 22, backcontact 21 of rela SLR, wire 59, back contact 24 of relay SL wire 23, tothe opposite side of the winding oi relay Z. The openinglszf theenergizing circuit for the relay Z a opens the ener ing circuit of theindicating relay IR whic causes its contact to assume a deener zedposition illuminoting the indicator lig t I from the positive terminalof a suitable source of positive potential indicated as B through backcontact 65 of relay IR, wire 66, indicator lamp I, to the negativeterminal of the suitable source indicated as B With the indicating relayIR deenergized, the lock L is deenergized due to the openin of frontcontact 65 as is obviwire ous from the rowing, which condition causesits locking member 82 to assume a position reventlipfi movement of theswitch machine ever S Let us now assume that there is no train on thetrack section TiE and that the various route lockin other similarlocking relays and track relay are in ener 'tions, so that the sectionlocking role is ener- The indicator relay is now enerso that the lockingmember 62 of the ock L is actuated to an inactive position. Also, let usassume, that the operator moves he switch machine control lever SML tothe hand position which energizes the relay III Z with negativepotential through a circuit traced as follows :from the negativeterminal of battery BT, through wire 67, lever SML in a left-handextreme position, wire 19, winding of relay IR, wire 20, front contact21 of relay SLR, wire 22, winding of relay Z, wire 23, front contact 24of relay SLR, common wire C, to the midpoint of battery BT'. -\\'ith thereverse energizing circuit coniplcted for the relay Z, its polarcontacts and T0 are caused to assume a left-hand extreme position whichopens the holding circuit. of the controller CR and deenergizes therelay HR at the polar contact 25. The polar contact of relay Z, thus conpletes the energizing circuit of the coil Rb for controlling thecontacts of the circuit controller (R to right-hand extreme ositions, assoon as both the relays NI and 151 assume deenergized positions. Thisenergizing circuit for operating coil RC is traced as follows from thepositive terminal of a suitable source of electrical potential indicatedas 13+, through back contact 71 of relay NI, wire 72, polar contact 70of 'relay Z in a left-hand extreme position, wire 73, 'coil RC, wire 74,contact 7 5 of circuit controller CR, wires 76 and 77, front contact 78of relay T, wire 79, front contact 80 of relay SLR, wire 81, backcontact 82 of relay NI, wire 83. back contact 84 of relay RI, to theopposite tcrminal of the suitable source indicated as B. It will henoted that the contact 75 is a breakeyond-center contact, which insuresthat the mechanical toggle arrangement will cause the reverse contactsto he made.

The contacts of the circuit controller CR are now operated to right-handreverse extreme positions, in which positions a circuit is completed foroperating the switch machine SM to a reverse position and thus controlthe track switch TS to a corresponding position. This reverse operatingcircuit for the switi h machine SM is traced as follows from the"positive terminal of a suitable source indicated as 13+, through contact85 of circuit controller GR in a right-hand reverse position, wire 86,armature A, wires HT and 88, contacts 5-89, wire contact 91 of circuitcontroller GR in a right-hand reverse position, wire 92, field windingF, wire 923, winding of brake BR, to the opposite terminal of thesuitable source indicated as B The switch machine SMnow unlocks thetrack switch TS and operates it to a reverse extreme position in theusual well known manner. at the completion of which the movable contact5 is operated to a reverse position opening the energizing circuit ofthe switch machite at contacts 5-89.

As soon as the switch machine SM unlocks the track switch TS. the normalenergizing circuit of the switch re eating relay SR is further openeddue to t e operation of the point detector contacts PD. The movablecontact. block 6 is operated to an intermediate position which causesthe normal energizing circuit of the relay SR to he further opened atthe contacts 7-452 and 837. Also, the shunt contact 5) assumes acontacting position thus shunting the relay SR from its left-handterminal through Wire 35, shunt contact S1 in a contacting position,wire 94, shunt contact 10 in a contacting position, wire Ill, to theleftshand terminal of relay SR, which causes the neutral contact 40 toassume a dccnergized position during the operation of the track switchTS or at any such time that it is unlocked.

It will he noted, that should the operator fail to return the signalcontrol lever SL to a central position, the signal S would be put tostop immediately as soon as the control relay Z reached a new governingposition, due to the deenergization of the switch repeating relay SR andthe normal indicating relay NI. In other words, the clearing of a signaldepends u on the energization of either relay NI or I and thedeenergization of one of them, while the operation of the switch machinedepends upon the deenergization of both of said relays.

When the track switch TS has been operated to an extreme reverse lockedposition, the movable contact block 6 is operated to an extreme reverseposition and the shunt contact 10 is actuated to a non-contactingposition, which completed the reverse cner izing circuit for the switchrepeating relay S l and included therewith the reverse holding circuitof the circuit controller OR.

The reverse energizing circuit for the switch repeater relay SR istraced as follows :from the positive terminal of a suitable source ofelectrical potential indicated as 13+, through back contact 71 of relayNI, wire 72, contact 700i relay Z in a left-hand position. wire 73,reverse operating coil RC, wire 74, contact 75 in a right-hand reverseposition, wire 98, contacts 8-99, wire 100, shunt contact 9 in acontacting position, wire 35, winding of relay SR, wires 34 and 101,contacts 'i'102, wire 38 to the negative terminal of the suitable sourceindicated as B As the current in the winding of relay SR is flowing in areverse direction, the polar contact 41 is actuated to a right-handreverse position, after which the neutral contact 40 is actuated to anenergized position. The reverse indicating relay BI is now energizedthrough a circuit traced as follows :from the positive terminal of asuitable source of electrical potential indicated as B+, through frontcontact 40 of relay SR, wire 45. polar contact 41 of relay SR in a righthand position, wire 103 windin of relay RI, wire 104- hack contact 105of reIay NI, to the negative terminal of the suitable source indieatedas B.

With the reverse indicating relay RI energized, the signal S' may becaused to give a proceed indication for the passage of traffic in aneast-bound direction over the track switch TS onto the passing sidingPS. This is accomplished by the movement of the control lever SL to aleft-hand position which places negative potential upon the controlrelay Z from the negative terminal of battery BT through wire 106, leverSL in a left-hand position, wire 50, winding 0 relay Z common wire C tothe mid-point of battery ET. The polar contact 53 of control relay Z isnow actuated to a lefthand reverse position and the neutral contact 51is actuated to an energized position, which completes the circuit forsignal S. This energizing circuit for the I signal S is traced asfollows :-from the positive terminal of a suitable source of electricalpotential indicated as B+ through front contact 51 of relay Z wire 52,polar contact 53 in a left-hand position, wire 107, front contact 108 ofrelay RI, wire 109, back contact 110 of relay.NI, wire 111, through thecontrol devices of signal S", to the negative terminal of the suitablesource of potential indicated as 13-.

Assuming that a train passes onto the detector track section TE, thenceover the track switch TS onto the passing siding PS, the track relay Tis deencrgized in the usual manner which results in the deenergizationof the indicator relay IR. and the lever lock L in the same manner asheretofore explained. Thus, indication is given in the tower of thepassage of a. train over the detector track sect'on TE by theillumination of the indicating lamp I. Also, the switch machine controllever SML is prevented from being operated to a new position with thelocking member 62 of lock L in an active position.

Assume the detector track sections to be unoccupied, then the controllever SML may be returned to its normal position, thus controlling thetrack switch TS to its normal position in an operation which is merelyan inverse function of the operation of the system from the normalcondition to reverse condition'as just described in detail.

From the above descri tion, it is obvious that the governing signal Sand S cannot give clear or proceed indications during the operation ofthe switch machine SM, or conversely, the switch machine cannot beoper-' ated unless said governing signals display their most restrictiveindications. In other words, as soon as the'switch machine control leveris operated to a new position, the polar contacts ofthe control relay Zare operated to new positions which opens the circuit of the normal andreverse indication repeating relays NI and RI which must then assumedeenergized positions before the switch maf establishment of the severalroutes.

chine circuit controller CR can be operated. When the indicationrepeatin relays N1 and RI assume deenergized positions to permit theoperation of the circuit controller OR, the clearing circuits for thesignals S and S are necessarily open at a front contact.

The above description points out the various conditions governing thesignals S and S which are involved in the manuiil n other words, thesignal circuits are interlocked with the associated switch machinecontrol to prevent the false or improper clearing of a signal and toprovide that it shall give its most restrictive indication before theestablished route may be changed.

The signals are also under the control of an operator. which controlallows the signals to be caused by the operator to give most restrictiveindications at any time, and allows the circuits to be conditioned b theoperator for the signals to give clear in ications when the remainingconditions, not under the control of the operator, are such as to permitthe clearing of the signals. These remaining conditions include thoseestablished by the interlocking as pointed out above and also preferablyinclude conditions established in accordance with the traflic passingthrough the established route. Such traffic conditions govern thesignals by automatic control means operated by the track circuits of thevarious routes, which automatic means is associated with the signals ina manner well known in the art, and is omitted for the sake ofsimplicity in the present disclosure.

By the provision of the lever lock L, the operations of the switchmachine control lever SML and the control relay Z are coordinatedalthough the intervening control circuits are open at certain times fortransmitting the indication of detector track section occupancy. Also,premature switch machine lever movement is prevented before theassociated track switch is in condition to receive such control.

It may be further noted, that the switch repeating relay SR not onlyindicates the position and locked condition of the track switch TS, butalso indicates the correspondence of the circuit controller CR and thecontrol relay Z with said switch TS. This interlocking of controloperations and indication condiiions pre ents the clearing of anygoverning signal to permit the passage of a train, when any one of saidelements are out of correspondence, which lack of correspondence mightotherwise result in the operation of the track switch to an unlockedcondition without proper authorization during the passage of a train.

Having described rather specifically an interlocking system embodyingthe present in- 6 1,sa4,1a1

vention, it is to be understood that the various circuits and devicesincluded in this embodiment are used to facilitate in the disclosure ofthe invention, rather than to determine the s ecific nature and scope ofthe invention;

a so, it is to be understood that various modi-'.

fications, adaptations and alterations may be made to the interlockingsystem embodying the present invention to meet the varying reuirementsof practice without departing Irom the spirit or scope of the presentinvention, as set forth in the appended claims.

Having described my invention, 1 now claim 1. In an interlocking systemfor railroads, a track switch having a detector track section a switchmachine for operating said track switch, a control lever, a controlrelay for governing said switch machine said relay being controlled bysaid control lever, means indicating in the tower the occupancy of saiddetector track section and locking means preventing movement of saidcontrol lever to a new governing position during the indication ofoccupancy of said detector track section.

2. In an interlocking system for railroads, a track switch having adetector track section, a switch machine for operating said trackswitch, a control lever, a control relay for governing said switchmachine, said relay being controlled by said control lever over apolarized line circuit, an indicating relay included in series in saidpolarized line circuit,

means for breaking said polarized line circuit during occupancy of saiddetector track section, whereby both said control and said indicatingrelays are deenergized, and locking means effective to prevent movementof said control lever to a new governing position when said indicatingrelay is deenergized.

3. In an interlocking system for railroads, a track switch, a switchmachine having normal and reverse operating circuits, a two-positioncircuit controller for closing said operating circuits, a two-positioncontrol relay governed from the tower, means causing said circuitcontroller to be operated to a position in correspondence with saidcontrol relay, an indication relay giving indication of thecorrespondence of said control relay and said circuit controller withsaid track switch, holding circuits for said circuit controllerincluding said indication relay completed when said track switch is incorrespondence with said control relay and said circuit controller, andsignals governed b said indication relay.

4. in an interloc ring system for railroads. a track switch, a switchmachine, a circuit controller for controlling said switch machine, acontrol relay operated from a distant point for controlling said circuitcontroller, a plurality of relays indicating the position and lockedcondition of said track switch and also thecorrespondence of saidcontrol relay and said circuit controller with said track switch, aplurality of signals governing traific over said track switch andselected by said indication relays, means preventing operation of saidcircuit controller until said indication relays 've indication'of thenon-correspondence 0 said control relay with said circuit controller,and means, including said indication relays, for insuring thenon-selection of said signals except when said control relay and saidcircuit controller are in correspondence with said track switch.

5. In an interlocking system for railroads, a track switch, a switchmachine having normal and reverse operating circuits, signals governingtraffic over said track switch, a two-position circuit controller of themechanical stick type for controlling said switch machine a two-positionrelay operated from a remote point, said relay operably governmg saidcircuit controller, an indication relay giving one indication when saidtrack switch is in a normal locked position with said control relay andsaid circuit controller in correspondence therewith, giving anotherindication when said track switch is in a reverse locked position withsaid control relay and said circuit controller in correspondencetherewith, and giving a third indication when said track switch isunlocked or when either said control relay or said circuit controller isout of correspondence with said track switc two indication operatingrelays, one of which is energized when said indication relay gives saidone indication, the other of which is energized when said indicationrelay gives said other indication, and both of which are deenergizingwhen said indication relay gives said third indication. means preventingthe operation of said circuit controller except when both saidindication repeating relays are deenergized. and means preventing theclearing of said signals when both of said indication repeating relaysare deenergized.

6. In an interlocking system for railroads, a track switch, a detectortrack section associated with said track switch, a switch machine foroperating said track switch, a control lever, a control relay governedby said control lever over a polarized line circuit for causing saidswitch machine to operate, signals governing trailic over said detectortrack section, manually controlled means for clearlng said signals,means causing said manually controlled means to be inefi'ectivc to clearsaid signals when said switch machine is in operation, and meanspreventing the operation of said switch machine during occupancy of saiddetector track section.

7. In a railroad traiiic controlling system, a track switch, a switchmachine for operating said track switch, a two-position circuitcontroller for governing said switch machine, a remotely controlledrelay, operating circuits for said two-position circuit controllergoverned by said remotely controlled relay, holding circuits for saidtwo-position circuit controller governed by said'remotely' controlledrelay, a detector track section, means opening the operating circuits ofsaid twoposition circuit controller when said detector track section isoccupied, and means preventing operation of said remotely Controlledrelay when said detector track section is occupied.

8. In a railroad traflic controlling system, a track switch, a switchmachine foroperating said track switch, a two-position circuitcontroller for governing said switch machine, a remotely controlledrelay, operating circuits for said two-position circu t controllergoverned by said remotely controllcd relay, holding circuits for saidtwo-position circuit controller governed by said remotely controlledrelay, a detector track section, means opening the operating circuits ofsaid two-posltion circuit controller when said detector track section isoccupied, and means preventmg the opening of said holding circuits forsaid two-position circuit controller when said detector track section isoccupied.

9. In a railroad trafllc controlling system; a track switch; poweractuated means for operating said track switch; an electro-responsivedevice for governing said power actuated means, said device beingremotely controlled; indication means for indicating the position andlocked condition of said track switch, said indication means beingresponsive to the correspondence between said electro-responsive deviceand said track switch; and signals governed by said indication means.

10. In a railroad trafiic controlling system a track switch operable tonormal or reverse extreme positions; a power actuated means foroperating and locking said track switch in either of said extremepositions; a manually controlled electro-responsive device for governingsaid power actuated means; point detector contacts operated by saidtrack switch to opposite extreme positions in accordance with the normalor reverse extreme position of said track switch and actuated tointermediate positions when said track switch is unlocked; an indicatingrelay; operating circuits for said indicating relay governed by saidpoint detector contacts and said manually controlled electro-responsivedevice, whereby said indicating relay is caused to indicate thecondition of corres ondence between said manually controlledelbctro-responsive device and said track switch and also to indicate thenormal or reverse position of said track switch together with its lockedor unlocked condition; and signals selected by said indicating relay.

11. In a railroad trailic controlling system, a track switch, a switchmachine for operating said track switch, a circuit controller forgoverning said switch machine, point detector contacts operated by saidtrack switch and said switch machine jointly, a remotely controlledrelay, an indication relay, operatin circuits for said circuitcontroller governs by said indication relay and said remotely controlledrelay, holding circuits for said circuit controller governed by saidremotely controlled relay and said point detector contacts said holdingcircuits including said indicating relay, whereby said indicating relayindicates the position and locked condition of said track switchtogether with the condition of correspondence between said remotelycontrolled relay and said circuit controller with said point detectorcontacts, and signals selccted by said indicating relay.

12. In a railroad tra c controlling system, a railroad track switch,power actuated means for operating said track switch, anelectroresponsive device for actively governing said power actuatedmeans when said electro-responsive device is operated out ofcorrespondence with said track switch, indication means indicating theposition and locked condition of said track switch, means causing saidindication means to give an indication corresponding to the unlockedcondition of said track switch when said electro-responsive deviceis'actuated out of correspondence therewith, and trafiic controllingmeans governed by said indication means.

13. In a railroad trafiic controlling system, a railroad track switch,power actuated means for operating said track switch, anelectro-responsive device for actively governing said power actuatedmeans when said electro-responsive device is operated out ofcorrespondence with said track switch, indication means indicating theposition and locked condition of said track switch, means causing saidindication means to give an indication corresponding to the unlockedcondition of said track switch when said electro-responsive device isactuated out of correspondence therewith, and means preventing saidelectro-responsive means from actively governing said power actuatedmeans until said indication means gives an indication correspondin tothe unlocked condition of said track swltch.

14. In a railroad trafiic controlling system, a railroad track switch,power actuated means for operating said track switch, anelectro-responsive device for actively governing said power actuatedmeans when said electro-responsive device is operated out of correspondence with said track switch, indication means indicating the positionand locked condition of said track switch, means causing said indicationmeans to give an indication corresponding to the unlocked condition ofsaid track switch when said electro-responsivedevice is actuated out ofcorrespondence therewith, means preventing said electro-responsive meansfrom actively governing said pow- \l actuated means until saidindication means gives an indication corresponding to the unluckedcondition of said track switch, and other traflic controlling meansgoverned by said indication means.

L). In an interlocking system for railroads, :1 track switch, a switchmachine for operating said track switch, means for controlling saidswitch machine, signals governing trafiic over said track switch, meansfor manually clearing said signals, means causing said signals to givemost restrictive indications upon operation of said means forcontrolling said switch machine irrespective of said means for manuallyclearing said signals, means requiring said signals to give mostrestrictive indications before said switch nmchine can be controlled bysaid means for controlling said switch machine, and means preventingoperation of said means for controlling said switch machine during thepassa e of traffic over said track switch.

n testimony whereof I aflix my signature.

FRANK L. DODGSON.

15. In an interlocking system for railroads, a track switch, a switchmachine for operating said track switch, means for controlling saidswitch machine, signals governing traffic over said track switch, meansfor manually clearing said signals, means causing said signals to givemost restrictive indications upon operation of said means forcontrolling said switch machine irrespective of said means for manuallyclearing said signals, means requiring said signals to ive mostrestrictive indications before said switch machine can be controlled bysaid means for controlling said switch machine, and means preventingoperation of said means for controlling said switch machine during thepassa e of trafiic over said track switch.

n testimony whereof I afiix my signature.

FRANK L. DODGSON.

DISCLAIMER 1,824,127.Frank L. Dodgson, Rochester, N. Y. INTERLOCKINGSYSTEM FOR RAIL- ROADS. Patent dated Sgptember 22, 1931. Disclaimerfiled July 28, 1934. by the assignee, General azlway Signal Company.

Hereby enters this disclaimer to claims 6, 7, 8, and 15 of said LettersPatent, which are m the following words, to wit:

6. In an interlocking system for railroads, a track switch, a detectortrack section associated with said track switch, a switch machine foroperating said track switch, a control lever, a control relay governedby said control lever over a polarized line circuit for causing saidswitch machine to operate, signals governing traffic over said detectortrack section, manually controlled means for clearing said signals,means causing said manually controlled means to be ineffective to clearsaid signals when said switch machine is in operation, and meanspreventing the operation of said switch machine during occu ancy of saiddetector track section.

'2'. In a railro traffic controlling system, a track switch, a switchmachine for operating sa d track switch, a twoosition circuit controllerfor governing said switch machine, a remotely controlle relay, operatingcircuits for said two-position circuit controller. governed by saidremotely controlled relay, holding circuits for said two-positioncircuit controller gpverned by said remotely controlled relay, adetector track section, means opening t e operating circuits of saidtwo-position circuit controller when said detector track section isoccupied, and means preventing o eration of said remotely controlledrelay when said detector track section is occu ie "8. In a railroadtraflic controlling system, a track switch, a switc machine foroperating said track switch, a twoosition circuit controller foroverning said switch machine, a remotely controlled re aly, operatincircuits for said two-position circuit controller governed b said remotey controlle relay, holding circuits for said twoposition circuit controer governed by said remotely controlled relay, a detector track section,means opening the operating circuits of said two-position circuitcontroller when said detector track section is occupied, and meanspreventing the opening of said holding circuits for said two-positioncircuit controller when said detector track section is occupied.

15. In an interlocking system for railroads, a track switch, a switchmachine for operatin said track switch, means for controlling saidswitch machine, signals governing trafl'ic over said track switch, meansfor manually clearing said signals, means causing said signals to givemost restrictive indications upon operation of said means forcontrolling said switch machine irrespective of said means for manuallyclearing said signals, means requiring said si ale to give mostrestrictive indications before said switch machine can, be contro ed bysaidmeans for controlling said switch machine, and means preventing oeration of said means for. controlling said switch machine during thepassage of tra c over said track switc [Qflicial Gazette August 21.1984.1

DISCLAIMER 1,824,127.Frank L. Dodgson, Rochester, N. Y. INTERLOCKINGSYSTEM FOR RAIL- noans. Patent dated Se temher 22, 1931. Disclaimerfiled July 28, 1934. by the assignee, General l ailway Signal Company.Hereby enters this disclaimer to claims 6, 7, 8, and 15 of said LettersPatent, which are in the following words, to wit:

6. In an interlocking system for railroads, a track switch, a detectortrack section associated with said track switch, a switch machine foroperating said track switch, a control lever, a control relay governedby said control lever over a polarized line circuit for causing saidswitch machine to operate, signals governing traffic over said detectortrack sectioii, manually controlled means for clearing said signals,means causing said manually controlled means to be ineffective to clearsaid signals when said switch machine is in operation, and meanspreventing the operation of said switch machine during occu ancy of saiddetector track section.

7. In a railro traflic controlling system, a track switch, a switchmachine for operating said track switch, a twoosition circuit controllerfor governing said switch machine, a remotely controlled relay,operating circuits for said two-position circuit controller. governed bysaid remotely controlled relay, holding circuits for said two-positioncircuit controller overned by said remotely controlled relay, a detectortrack section, means opening 510 operating circuits of said two-positioncircuit controller when said detector track section is occupied, andmeans preventing o eration of said remotely controlled relay when saiddetector track section is occu ie 8. In a railroad traffic controllingsystem, a track switch, a switc machine for operating said track switch,a twoosition circuit controller for overning said switch machine, aremotely controlled re a operatin circuits for said two-position circuitcontroller governed b said remote] controlle relay, holding circuits-for said twoposition circuit contr her governed by said remotelycontrolled relay, a detector track section, means opening the operatingcircuits of said two-position circuit controller when said detectortrack section is occupied, and means preventing the opening of said mgtr 0 over said track switch, means for manually clearing said signals,means causing said signals to give most restnctive indications uponoperation of said means for controlling said switch machinejrrespectiveof said means for manually clearing said signals, means requiring saidBIfiHBlB to give most restrictive indications before said switch machinecan be contro ed by said-means for controlling sa d sw tch machine, andmeans preventing o eration of said means for. controlling said switchmachine during the passage of tr 0 over said track switch."

[Qflicial Gazette August 21. 19311.1

